sinus

noun

si·​nus ˈsī-nəs How to pronounce sinus (audio)
: cavity, hollow: such as
a
: a narrow elongated tract extending from a focus of suppuration and serving for the discharge of pus
b(1)
: a cavity in the substance of a bone of the skull that usually communicates with the nostrils and contains air
(2)
: a channel for venous blood
(3)
: a dilatation in a bodily canal or vessel
c
: a cleft or indentation between adjoining lobes (as of a leaf or corolla)

Examples of sinus in a Sentence

Recent Examples on the Web
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
Bon Jovi did, however, end the July 23 MSG concert slightly early due to a sinus infection. — Andy Greene, Rolling Stone, 27 July 2026 Bon Jovi has faced some vocal issues during his residency at MSG and even cut his show short on Thursday due to symptoms of a sinus infection. — Leigh Blickley, Entertainment Weekly, 27 July 2026 The band cut the Madison Square Garden gig short after about 90 minutes and 14 songs because frontman Jon Bon Jovi is battling a sinus infection. — Melissa Ruggieri, USA Today, 24 July 2026 During a tour of the facilities, Merinoff Kwasnieski walked me around the warehouse, encouraging me to take a whiff from a bin of fermenting strawberries (jammy and clear-your-sinuses boozy, all at once). — Molly Fergus, Travel + Leisure, 23 July 2026 See All Example Sentences for sinus

Word History

Etymology

Middle English, from Medieval Latin, from Latin, curve, fold, hollow

First Known Use

15th century, in the meaning defined above

Time Traveler
The first known use of sinus was in the 15th century

Phrases Containing sinus

Rhymes for sinus

See All Rhymes for sinus

Browse Nearby Words

sinuous
sinus
sinus gland
See all Nearby Words

Cite this Entry

“Sinus.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/sinus. Accessed 5 Aug. 2026.

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Kids Definition

sinus

noun
si·​nus ˈsī-nəs How to pronounce sinus (audio)
: a hollow place : cavity
especially : any of several cavities in the skull that usually connect with the nostrils

Medical Definition

sinus

noun
si·​nus ˈsī-nəs How to pronounce sinus (audio)
: a cavity or hollow in the body: as
a
: a narrow elongated tract extending from a focus of suppuration and serving for the discharge of pus
a tuberculous sinus
b(1)
: a cavity in the substance of a bone of the skull that usually communicates with the nostrils and contains air
(2)
: a channel for venous blood
(3)
: a dilatation in a bodily canal or vessel

More from Merriam-Webster on sinus

Nglish: Translation of sinus for Spanish Speakers

Britannica.com: Encyclopedia article about sinus

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